Drilling directional and/or horizontal wells requires the use of a survey tool, referred to as a steering tool, to monitor the well bore path and monitor the orientation of the drilling assembly. One method of transmitting the survey information required to measure the orientation of the drill bit and well bore path is by use of an electrical conductor connected between the steering tool and the well surface for conducting signals.
Horizontal or high angle well bores, unlike conventional vertical well bores, are used to drill long well bore intervals in the target pay zone. As a result, many horizontal wells are drilled live (producing oil/gas) which requires the use of blowout control equipment at the well surface and around the outside of the drill string. This requires that the electrical conductor conducting signals from the steering tool to the well surface be inside of the drill string.
In directional and/or horizontal drilling, steerable drilling motors or rotary drilling assemblies are used to drive a drill bit to drill a controlled well path. This technology requires a combination of drill string rotation and slide drilling to control the direction and inclination of the drill path. Conventional wireline steering techniques prevent drill string rotation while the steering tool is downhole and connected through an electrical conductor to the well surface. Pulling the electrical conductor and/or steering tool for string rotation is not always economical or achievable in high angle and horizontal drilling due to seating problems. These problems are further magnified as the wireline electrical conductor from the well surface to the steering tool must be lengthened or shortened as additional pipe joints are added to or subtracted from the drilling string as drilling continues. This creates additional problems of support of the electrical conductor in deep wells.
The present invention is directed to the use of a connectable and releasable electrical wet connect for use in a wireline electrical conductor, such as used for transmitting electrical signals through a well drill string. In particular, a steering tool is used to monitor tool face orientation and to survey the well path in directional and/or horizontally drilled wells. The present wet connect can be telescopically connected and disconnected in the drill string as required, as the drill string is lengthened and shortened. When connected, the present wet connect electrically isolates the transmitted power or electrical signal from electrical ground and from the drilling fluid. This allows free electric communication between the steering tool and the surface support equipment. In addition, drill string rotation for steerable drilling assemblies is not hampered by the electrical conductor and wet connect due to its construction and operation. Furthermore, because of the present wet connect, the wireline electrical conductor may be quickly positioned so as not to interfere with the addition to or the subtraction of pipe joints to the drill string.